Roof support assembly of the type used on the longwall face of a coal seam



April 15, 1969 K. GREBE 3,438,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COALSEAM Filed May 27, 1965 Sheet of 9 mun/rap K. GREBE April 15, 1969 ROOFSUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALLFACE OF A COAL SEAMSheet g of 9 Filed May 27, 1965 3,438,209 USED ON THE EAM April 15, 1969K. GR EBE ASSEMBLY OF THE GWALL FACE OF A COA TYPE Sheet 3 of 9 r m N Ew N N R m w n w Q Q 0 T Q Q Q wmw flw wwwmfifi Q l w mw I.- H m IPI i 1l 4 R mm NM NM @GI N x p R w m p 2 f I G IWWHWI I .lH H x L O m J EIQ BM Q NM W NR sw m mi R a N m a M W r o o H inmnw w QMW J Q/NWQ wwmx %.@I2 9m $701M WM Vat mm P" 5, 1969 K. GREBE 3, 38,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COALSEAM Filed May 27, 1965 7 Sheet 4 of 9 nvnw rap April 15, 1969 K. GREBE3,438,209

ROOF SUPP ASSEMBLY OF THE TYPE USED ON THE L N WALL FACE OF A COAL SEAMSheet 5 of 9 Filed May 27, 1965 FIG. 76

INVENTOR K. GREBE April 15, 1969 3,438,209 ROOF SUPPORT ASSEMBLY OF THETYPE USED ON THE LONGWALL FACE OF A COAL SEAM Sheet Q of 9 Filed May 27,1965 E 8 S T 3% mow wt Qw W2 mm 1 i 1 W W M w mm m H m qGN 6t April 15,1969 K. GREBE 3,438,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COALSEAM Sheet 7 of 9 Filed May 27, 1965 MNN GE NNGI www wt April 15, 1969K. GREBE 3,433,209

ROOF SUPPORT ASSEMBLY OF THE E USED ON THE LONGWALL FACE OF A C SEA-MFiled May 27, 1965 Sheet 8 of 9 INVENTOR.

BY KONRAD GREBE Apnl 15, 1969 K. GREBE 3,438,209

ROOF SUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COALSEAM Filed May 27, 1965 Sheet of 9 I N VENTOR.

FIG. 24 koNRAD EQBE A-n'r u c-IV United States Patent 3,438,209 ROOFSUPPORT ASSEMBLY OF THE TYPE USED ON THE LONGWALL FACE OF A COAL SEAMKonrad Grebe, Auf dem Nutzenberg 1, Wuppertal-Elberfeld, Germany FiledMay 27, 1965, Ser. No. 459,237 Int. Cl. EZld 11/00 US. Cl. 6145 12Claims ABSTRACT OF THE DISCLOSURE A roof support assembly for longwallface mining consisting of two frames guided one on the other by means ofa guiding element arranged between both frames, such guiding elementbeing connected with both frames in such manner that the frames can moveas such, universally in their plane, either in an upward or lengthwisedirection within certain limits. This is achieved by interconnectingeach of the frames with the guiding element by two organs, one of whichenables pivoting to an upward movement and lengthwise displacement, andthe other of which affords at least pivoting of the frame in its plane.The connecting organs which afford the pivotal movement of the frame caneither be elements shiftable in an upward direction and along theguiding faces of the guiding element in a lengthwise direction, orpivots arranged on the respective ends of the guiding element orpivoting arms arranged on the respective ends. Preferably, doublepivotal arms are connected with one another by a pivot of scissors form,one of the arms being provided with a pivot fixed on the guiding elementand the other with a pivot fixed on the frame.

The present invention relates to a roof support assembly of the typeused on the longwall face of a coal seam formed by two frames each ofwhich consisting from an upper cap abutting to the roof and a lower capresting on the floor and props connecting these caps with one another,said frames being alternately released and advanced to the coal face andreset in the advanced position.

When the frames of this type of support assembly are advancedalternately one of the frames is released from engagement with the roofand is guided in its advancing movement on the other frame which remainsclamped in position between the roof and floor, thus ensuring that theframes always remain parallel to each other in the thrust direction ofthe support.

A system is already known in which this guiding is achieved byinterposing between the roof and the floor struts of the two framesforming the support assembly, a guide member which is longitudinallydisplaceable in relation to these struts and which engages in connectingmembers being located on the struts.

While this known system ensures that the frames always maintain theirrelative parallelism when one or the other is being advanced, it doesnot take account of the fact that both the floor and the roof strutsmust be vertically displaceable independently from one another so as toaccommodate the changing contours of both the floor and the roof. Morespecifically it should be possible for such changes in the contour ofthe floor and the roof to be compensated by raising or lowering one orboth ends of the strut on one frame which is then higher or lower, asthe case may be, than the corresponding strut on the adjacent frame inthe assembly.

:It is also known to provide means in support assemblies of the typedescribed above which allow vertical displaceability or movement in theconnecting members which link the frames to the guide member and ensureparallel advancement of the frames. While such a linkage arrangementdoes permit the struts on one frame to be set at a different level tothose on the adjacent frame, it is still necessary for them to run at alevel parallel to the guide member, and thus to each other, so thatlittle is gained insofar as the adaptability of the struts is concerned,particularly where irregularities of substantial magnitude areencountered in floor and roof contours.

It is an object of the present invention to eliminate this shortcomingin the above-described known assemblies by enabling random and completeadaptation of the setting of the'floor and roof struts relative to boththe floor and roof contours.

According to the present invention there is provided a roof supportassembly comprising a pair of relatively movable frames each of whichcomprises a fioor strut and a roof strut joined by two or more verticalprops and a guide member interposed between the roof and/or floor strutsand adapted to constrain relative movement between the two frames,wherein each frame is connected to its guide member by two connectingmembers, one of which allows pivoting movement, longitudinaldisplacement and vertical displacement of the frame relative to theguide member and the other of which connecting members allows at leastpivoting movement of the frame relative to the guide member.

The vertically displaceable and pivoted connecting members for the guidemember can, for example, take the form of narrow dog attachments orsliding blocks, which are longitudinally slidable in a dovetail grooverunning along the entire length of the guide member and which engage inthe grooves on the opposite side of the strut, in which position theyare both vertically displaceable and pivoted about an axis runningtransverse to the strut.

At the ends of the grooves limit stops are provided to prevent theescape of the sliding blocks. If the two ends of the guide member arenot connected with the strut it is then necessary to provide a secondslotted guideway thus ensuring accurate parallel guidance.

In a modification of the invention the connecting members are in theform of magnets, which are vertically displaceable and pivoted on thestrut about an axis running transverse to the strut, the pole surface ofthe magnets being parallel to the sidewall of the guide member, withwhich they are in direct holding contact and which, in this embodimentcan be formed without any rail or groove.

As the guide member moves, its sidewall is moved past the magnets, whichoffer only a comparatively minor resistance to this longitudinaldisplacement, but any tendency to complete separation is subjected tocomparatively high resistance.

In this modification at least the guide member which is interposedbetween the floor struts of the support assembly can be designed as athrust cylinder. For this purpose the guide member is provided with twosuperposed or adjacent cylindrical bores extending longitudinallythrough the guide member and in which the cylinder pistons are movablein opposite directions.

The length of the guide member corresponds to the spacing of thevertical props in one of the frames. Owing to its restricted length theguide member does not, under any circumstances, extend beyond the strutsof the two frames comprising the support assembly but will neverthelesscontact the struts of both frames over a sufficient length to ensureaccurate guidance when the frames are moved. The cylinder piston rodsare pivoted on the frames, preferably by means of a hinge pin mountedtransversely on a strut, so that while the struts are held parellel tothe piston rods and the guide member in the direction of movement of aforward stroke they are still able to function as vertical props inrelation to the latter.

According to a further embodiment of the invention thevertically-displaceable seating of the linkage system is notincorporated in parallel guides, as is the case with the above-describedembodiment, being instead of pivoted at the free ends of hinged arms aremounted pivotally on a horizontal axis on the strut and bothlongitudinally displaceable and swivelable in relation to the guidemember. The vertical position of the linkage system or connectingmembers is thus determined in each case by the angle formed by theseswivel arms in relation to the strut. In this case, also, whereappropriate, the connecting members lie above the floor struts or belowthe roof struts, as the case may be. In no case, however, does the freeend of the swivel arm extend beyond or below the longitudinallydisplaceable guide member to which it is attached, thus ensuring thatthe space delineated by the prop on the one side and the actual positionof the longitudinally displaceable guide members on the other is neitherreduced nor impaired.

Particular advantage is gained, if, in accordance with a further featureof the invention, the swivel arms referred to above are provided with aspring mounting, such as torsion bars. Where appropriate, this springmounting enables the mutual parallel guidance of the two framesincorporated in the support assembly to be altered should it provenecessary for any reason to change the thrust direction of the support.The springs should have sufiicient tensile strength to ensure thatconsiderable force is required to bring about any change in the thrustdirection of the support assembly and also to prevent the latter fromreacting to any forces normally anticipated in dayto-day operations.Thus the thrust direction of the support assembly can be changed only bydeliberate application of a powerful wedging or spreading force. Thisembodiment of the invention provides a particular improvement upon knownmethods for changing the thrust direction of a support assembly inasmuchas it dispenses with the necessity for relieving the pressure on eachindividual prop. As is quite generally known it can, under somecircumstances, be of considerable importance for the etficientfunctioning of a mechanized movable support assembly for either of thetwo frames embodied in the assembly to remain propped in position whilerelevant aljustments are made to its counterpart where it is necessaryto change the thrust direction.

Particular advantages can be gained if, in yet a further development ofthe invention, the connecting elements between the struts and thetelescopic guide member are constructed not merely as single swivel armsbut by means of a joint, this being most effectively achieved by meansof a pivot pin.

The scissor shape formed by the double swivel arms is closed in normalposition and opens as soon as the strut sinks or adopts an inclinedangle relative to the guide member. The main advantage of thisarrangement lies in the fact that, when the strut adopts an angularposition relative to the telescopic guide member the points at which thetwo members of this swivel arm are pivoted to their appropriate partscannot be displaced in relation to each other in the thrust direction ofthe frame.

This double swivel arm construction While it can be employed on otherembodiments of the invention can be combined in a notably advantageousfashion with a telescopic unit adapted for this purpose and whichcomprises two mated tubes which slide appropriately within each other.Each of the struts located at either side of the telescopic unit isassigned to one of the two tubes and connected therewith by theappropriate connecting member, this being vertically displaceablerelative to the telescopic unit and/or swivelable relative to the strut,at least two such connecting members being located on each strut. One ofthese connecting members is fastened in a longitudinally fixed locationon the tube assigned to the strut, thus ensuring that axial movement ofthe tube transmits a similar thrust to the strut, or vice versa. Thesec- 0nd (and where applicable, the third) vertically displaceableconnecting member should then serve merely to ensure an adequate degreeof lateral guidance for the struts, which, owing to the verticaldisplaceability of the connecting members, are able to adopt an angularposition in the vertical plane.

If, for example, the connecting member is a singlearmed swivel arm or isconstructed in such a manner that inclination of the strut causeslongitudinal displacement of one of the two points at which it ispivoted with the telescopic unit, the additional connecting member willhave to be attached to a longitudinally displaceable mounting on theguide member, e.g. in a dog attachment. In turn this produces theparticular advantage that the sliding dog is carried directly on one ofthe tubes in the telescopic unit, thus dispensing with any necessity forsupplementary guidance. The guidance is normally applied to the outertube or sleeve, whereby the sliding dog on the connecting memberdisplaces the strut assigned to the inner tube over almost the entirelength of the sleeve in conjunction with extension or contraction of thetelescopic unit, while the strut on the sleeve tube is displaced onlymarginally at the end of the tube by its relevant sliding dogattachment. The reciprocal action of the sleeve tube has no effectwhatsoever upon the motion of this sliding dog in its mounting, sincestrut and sleeve tube movement are simultaneous. Only if the strutadopts an angle relative to the sleeve tube during this movement isthere a marginal movement on the part of the dog, but this can quiteeasily be deflected to the inner tube by appropriate shortening of thesleeve tube.

Each telescopic unit can also consist of a double set or arrangement ofappropriate tubes. In such cases each of these assemblies is attached toone of the two struts and each strut then is joined to its appropriateassembly with the aid of a connecting member mounted in a longitudinallyfixed seating on the outer tube which forms the sleeve of the unit andby at least one additional connecting memher which is verticallydisplaceable and is also fastened to the appropriate sleeve tube or to aconnecting member which is longitudinally displaceable along the sleevetube. It is thus necessary to make identical provision to those outlinedin the foregoing text, merely simplified by dispensing with theattachment of the one strut on the inner tube. When the telescopicarrangement is extended, the sleeve tube of the one assembly must alwaysmove in conjunction with the inner tube of the other assembly, so thatthe two assemblies must be interconnected in inverse relationship toeach other. This ensures mutual conformity of movement of the strut onthe one hand and the sleeve of its appropriate tube assembly on theother, following the identical pattern of behaviour to the struts andappropriate tubes involved in a single assembly oftelescopicallydisplaceable tubes.

The support is moved in the conventional manner releasing one of the twoframes and subjecting the released frame to a force which pushes itforward, the released frame being guided during its movement on thefixed frame of the support assembly. Since the frames can be movedforward by one complete prop space in each instance, this force can, forexample, be exerted by means of a rope led around the props in the pairof support frames and pulled by a winch located at the end of the frameassembly to be moved in longitudinal direction of the coal face. Theeffectiveness of the force to which the rope is subjected thereby is oflittle consequence in the region of those frame pairs which have alreadybeen moved, since the rope runs in an almost straight line at thatpoint. Since, as viewed from the winch, one frame is moved after theother in consecutive sequence, the rope grips the frame to be moved withfull force, or almost full force, and the pronounced angles of the ropein the area of frames which have not yet been moved has no adverseeffect upon overall efficiencyor, where it is necessary to move severalframes simultaneously, this arrangement causes the first frame to bepulled forward automatically faster than the second and third frames, asituation which can only be described as desirable, especially forpushing forward a conveyor supported on the frames or a backfill channelsuspended from the frames, or similar. The rope to be used for movingthe frames into the next stratum must naturally be led in front of theprops of those frames which have been moved forward and behind the propsof those frames still to be moved.

If the assembly is to be moved with the aid of thrust cylindersparticular advantages can be gained by incorporating the thrustcylinders in the sliding guide member by designing each of the twomutually displaceable tubes as a ram cylinder, the piston rod of whichis attached to the outer tube which functions as the sleeve.

In this case the sleeve tube represents a desired measure of protectionfor the piston rod, on the one hand by virtue of the fact that theforces which arise and are exerted in other than axial directions on thepiston rod, thus subjecting the piston rod to flexural stress and theinner walls and gaskets of the cylinder to undesirable pressures, areabsorbed by the sleeve tube which is located on the outer wall of thecylinder and on the other hand by virtue of the protection afforded thepiston rod against any possibility of foreign bodies being deposited onit and against jamming between the member connecting the piston rod withits appropriate strut on the one side and the cylinder on the other whenthe piston is retracted. Specifically this form of protection isachieved if the sleeve presents an uninterrupted surface rather thanbeing slotted. If the strut assigned to the cylinder is to be connectedat both ends by guide members secured on the cylinder, this necessitatesa fixed mounting on the cylinder of a further tube enclosing the sleevetube which is slidably connected with the piston rod. This tube may, inturn, be slotted in order to permit the connecting members to engagethrough the slot between the displaceable sleeve tube and theappropriate strut.

If, as is preferable, the connecting members are double swivel armsfundamentally of the type described above, the longitudinaldisplaceability of these double swivel arms is effected by theirattachment to a tube which, in turn, slides on another tube. Thus if twoconnecting members are fastened to the same tube, this is equivalent tothe dogs common to the two connecting members assigned to the samestrut.

Where such double-armed swivel arms are located as connecting members onboth ends of the strut this enables a flexible resistance to be achievedto the various reciprocal angling-off movements of the strut and thus toreduce these movements of the strut and thus to re duce these movementsto the degree found to be necessary in each case when advancing a frame.The swivel arms are positioned so that their ends, provided with thejoint between both arms, are opposed to each other and interconnected bya draw spring. This draw spring engages appropriately on the horizontalpivot pins of the swivel arms. This draw-spring may, however, bereplaced by torsion springs located on one axis of the swivel arms andbraced against a support in such a manner as to hold the arms parallelto the struts. It may also be expedient to prevent any undesirabledeflection movements when the frames are being advanced. This can beachieved with the aid of blocking devices which limit the angles of theswivel arms relative to the struts and/or relative to the guide member,as well as, where appropriate, angling of the two members of a swivelarm in relation to each other. Finally the draw spring has the importantadvantage that when the strut is to be moved forward by the guidemembers or member this movement is transmitted always from the front endof the advancing member via the swivel arm fastened to it and thedrawspring to the swivel arm fastened to the rear end of the othermember, thus ensuring that the motion is always a pulling rather than apushing action. Accordingly the drawspring must be of sulficientstrength to ensure that it cannot be pulled to an excessive length bythe shearing forces to which it may be subjected. Notwithstanding, theunimpaired movability of the joints which interconnect the ends of thedouble swivel arms still permits the struts to swivel relative to theguide member, as a result of which there is no displacement of theparallelogram.

Preferred forms of the invention will now be described with reference tothe accompanying diagrammatic drawings in which:

FIGURES 1 and 2 show, merely to illustrate the field of application ofthe invention, horizontal sections through a coalface propped withsupport assemblies in various stages of advance;

FIGURE 3 is an enlarged cross-section on the line IIIIII of FIGURE 4,but leaving out the roof struts;

FIGURES 4 to 6 are plan views of the frames of a support assembly, butomitting the roof struts, in three relative positions;

FIGURE 7 is a section on the line VII-VII of FIG- URE 6, through theguide member 10;

FIGURES 8 to 10 show the roof struts in positions corresponding toFIGURES 4 to 6'; I

FIGURES 11 and 12 are sections on the lines XI-XI and XIIXIIrespectively in FIGURE 9, but showing the roof struts of both frames inthe support assembly angled vertically in relation to each other; FIGURE13 is a plan view of a support assembly in which the longitudinallydisplaceable guide member is designed to accommodate the ram cylinderserving to advance the assembly when in start position.

FIGURE 14 is a plan view showing the assembly of FIGURE 13 on a reducedscale leaving out the roof struts and showing the floor struts in adifferent relative position;

FIGURE 15 is a side view of the assembly of FIG- URES 13 and 14accommodating a step in the floor of the seam;

FIGURES 16 to 19 are plan views of four pairs of support frames eachincorporating a different embodiment of a telescopic assembly;

FIGURE 20* to 22 are enlarged plan views of the advancing cylinders orrams associated with the telescopic assemblies of FIGURES 16, 17 and 18respectively;

FIGURES 20A and 20B are opposite end views respectively of the structureshown on FIGURE 20;

FIGURES 21C and 21D are opposite end views respectively of the structureshown on FIGURE 21; and

FIGURES 22E and 22F are opposite end views respectively of the structureshown in FIGURE 22.

FIGURE 23 is a perspective exploded view of one of the roof supportassemblies, including the floor strut, the props and guide member, andthe means in which the elements are connected and cooperating inaccordance with the structure shown on FIGURE 21; and

FIGURE 24 is a perspective exploded view of the parts shown on FIGURE 5.

As can be seen from FIGURE 1 and 2 a support assembly comprises twogroups of frames, the frames in the first frame group having verticalprops 3, 3, 3 and 4, 4', 4 which are interconnected by roof struts 1,1', 1" projecting on the coalface side and by floor struts 11, 11extending from prop to prop. The frames in the second group are formedby props 5, 5', 5" and 6, 6', 6" roof struts 2, 2, 2" and the floorstruts 12, 12'.

Between floor strut -11 of a frame in the first group and adjacent floorstrut 12 of a frame in the second group which is assigned to the samesupport assembly a guide member 10 is interposed, and a similar butsimplified guide member 30 (see FIGURES 11 and 12) is interposed insimilar manner between the roof struts 1 and 2 of the same assembly. Thesidewalls of the guide member 10 border on the upper and/or lower flangeof the struts 1, 2, 11, 12, which, for example, can be in the form ofdouble-T shaped girders, even if the struts are included in a verticalplane or displaced longitudinally in relation to each other. In additionboth sidewalls of the guide member are provided with swallowtail groovesThe guide member 10, the length of which corresponds to the distancebetween the props 3 and 4 of a frame in the first group, has twoadjacent cylindrical bores 20, extending longitudinally of the guidemember in one of which is housed a piston rod 21 which slides toward thecoalface While the other houses a piston rod 22 which slides out towardthe backfill side. The piston rod 21 has an articulated head 31 which isconnected by a hinge bolt 41 to the floor strut 11, 11', and the pistonrod 22 is connected in the same manner by an articulated head 32 andhinge bolt 42 to the floor strut 12 on the other frame.

In FIGURE 4 the upper flange of the strut 12 in the region of thisarticulated joint, which can, for example, be of a hinged type, has beenleft out in order to illustrate a practical embodiment of thearticulated joint.

When advancing through the coal stratum the frame bearing floor strut 11is first released so that it is supported by the guide member 10 whichis attached to the stationary floor strut 12 and is then advanced bypushing out the piston rods 21 and 22 into the position shown in FIGURE5. The articulated bolts 41, 42 serve as bearing points for the guidemember 10, and the sidewalls of the guide member 10' and grooves 10'guide the floor strut 11 on one side of the guide member 10 while theguide member 10 is itself guided on the other side in similar manner bythe floor strut 12. On the struts, such as 11 and 12, sliding blocks 51,52 are arranged to slide vertically in guides 71, 72. Furthermore, theblocks 51, 52 are shiftable in a lengthwise direction in grooves 10 ofthe guide member 10. By this arrangement, the parallel movement of thestruts 11, 12 is ensured while the position of the struts is altered ina lengthwise direction in the course of advancing and in a verticaldirection as a result of alterations or changes in the contours of theroof or floor. When the forward frame is settled in the advancedposition shown in FIGURE 5 the floor strut 12 is released and pulledinto place by drawing in the piston rods 21, 22, into the position shownin FIGURE 6.

FIGURES 8, 9 and 10 show the roof struts 1, 2, in correspondingpositions to FIGURES 4 to 6 with a simplified guide member interposedbetween them. The length of guide member 30 corresponds to the length ofthe floor strut 11 and a groove 30' in the guide member 30 has a stop ateither end which prevents the sliding blocks 61, 62 from escaping. Twosliding blocks 51, '52 are provided on each side of the guide member 30sliding in guideways 71, 72 on the struts 1, 2.

In FIGURE 3 the sliding block 52 is shown in its normal position, thatis the position when the ground is level. The sliding block 52 ismounted pivotally on the guide member 10 by means of cylindrical bolt 82which is a sliding T-head 62 and which is held on the link 52 by a rivethead 92. A similar slotted guide member and sliding block is shown inFIGURE 12. FIGURE 11, on the other hand, illustrates a circular slidingblock 61 which can pivot in the groove 30 and which is thereforeconnected rigidly to the slotted guide 51. FIGURES 11 and 12 also showthe position which the slotted guides 51, 52 assume in their guideways71, 73 when the struts 1, 2' are inclined upwardly towards the centre ofthe support assembly, in the shape of a roof, for instance because thefloor and the roof rises in the direction of props 4' and 5' and theprops 3 and 6 stand in a depression.

In FIGURES 13 to 15 the roof struts are also designated as 1, 2, thefloor struts as 11, 12, the props as 3, 4, 5, 6, the longitudinallydisplaceable guide members with their two superposed thrust cylinders as10 and the piston rods of these two cylinders as 21 and 22. The

longitudinally displaceable guide members 10 are pivoted on struts 2, 12of one frame by means of a swivel arm 25, 15 and via the telescopicpiston rods 22 with the aid of a pivot joint 42. They are pivoted onstruts 1, 11 by a swivel arm 24, 14 and via the piston rod 21 by a pivotjoint 41. The pivot joints 41, 42 are not displaceable longitudinally inthe direction of the struts, as it would otherwise be impossible totelescope the two frames to the same extent that piston rods 21, 22 canbe telescoped.

Consequently, the pivot joints 41, 42 must either be located in astationary position on the struts or, as shown in the figures be seatedin a guide member 51, 52 which is slidable in a guideway vertical to thelongitudinal plane of the struts or along the line formed by the props3, 6, the guideways 71, 72 allowing vertical, and only vertical movementof the pivot joints 41, 42.

FIGURE 15 shows the manner in which as a result of the end points of thelongitudinally displaceable guide member 'being movable vertically whenthe assembly is being advanced, it is possible to overcome a step in thefloor without difficulty. In order to keep the guide members as close aspossible to the height of the struts, a limit to the vertical movementof the end part of the guide member should preferably be marked beforecommencing the advancing process, for example by pegging, or they shouldbe subject, within the parallel guideways 71, 72, to the pressure of aspring acting in the appropriate direction. In FIGURE 15 the upper guidemember 10 which is attached to the roof struts 1, 2 is shown in a regionof the roof where the contours are normal. In the region of floor struts11, 12, the appropriate guide member 10 in order to overcome the stepeither adopts the inclined position illustrated or its entire length isaligned on a level with the floor strut 11. It can also assume aposition somewhere between these two positions. If the two end points ofthe lower guide member 10 are brought into the highest possiblepositions permitted by the parallel guideways 71 and 72, it is thenpossible to surmount steps of about double the height of that shown. Ina corresponding manner the assembly can also be advanced through troughsand over saddles.

The angular position of the swivel arms 14, 24 and 15, 25 which arepivoted about axles 34 and 35, respectively, which are located on theappropriate struts in relation to the strut and guide member, isdetermined by the position of the guide member 10, in the longitudinalgrooves 10' of which slide the connecting members 44, 45 located on thefree ends of the swivel arms. The connecting members 44 and 45 are inturn pivoted in relation to the swivel arms 14, 24 and 15, 25respectively or in relation to the guide members 10. If the swivel arms14, 24 and 15, 25 are provided with a spring mounting the frame havingstruts 1, 11 in the region of prop 4 and the frame having struts 2, 12in the region of prop 5 are supported to a certain extent by thelongitudinally displaceable guide member 10. By this means it ispossible to influence the thrust direction of the assembly and tofacilitate this the hinge pins 41, 42 are shaped spherical to asuificient extent to allow the amount of play or universal movementrequired.

FIGURES 16 to 23 illustrate three further embodiments of the inventionin which the connecting members between the struts and their appropriatecylinder are modified, FIGURE 16 corresponding with FIGURE 20, FIGURE 17corresponding with FIGURES 19 and 21 and FIGURE 18 corresponding withFIGURE 22.

In FIGURE 16 the floor strut 111 is connected to an inner tube and thefloor strut 112 is connected to a sleeve tube which slidestelescopically on the inner tube 120. FIGURE 20 is on a larger scale andshows the floor strut 112 drawn up to the strut 111 and also shows athrust imparting cylinder in place of the inner tube 120. In theembodiment illustrated in FIGURE 20 the sleeve 130 is attached to an endof the piston rod of the thrust cylinder 170, so that it is pulled inalong the cylinder when the piston is withdrawn and pushed out along thecylinder when the piston is expelled, since in this case the sleeve 130is attached to the strut of the fixed frame, the cylinder is pressed outof the sleeve.

At one end of the inner tube 120 (of cylinder 170) there is a lug onwhich a plate 151 is pivotally mounted by a pin 141, the plate beingvertically displaceable in a parallel guideway 171 on the strut 111. Thesleeve tube 130 has a recess at one end in which it accommodates theafore-mentioned lug when the telescope is collapsed (as in FIGURE 20) orit is shortened appropriately around the whole of its circumference (asin FIGURE 16). The strut 111 is also connected by a single-member swivelarm 124 to the sleeve tube 130. The swivel arm 124 is attached at oneend to the strut 111 on a pin 134 rotatable about its own axis. Twotorsion springs 137 and 138 are fastened to the pin 134, one of thesprings being braced against a support when the pin rotates in onedirection and the other spring being braced against the support when thepin rotates in the opposite direction, a suitable support being, forexample, a flange of the strut. While this is not discernible from thedrawing both springs are biased and locked. At the other end the swivelarm 124 pivots on a bearing 144 and is secured to a dog attachment 154,the latter partially encircling the sleeve tube 130 on which it islongitudinally displaceable.

The strut 112 is linked to the guide member in a similar manner via aconnecting member 142, 152 on the sleeve 130 which is verticallydisplaceable but not longitudinally displaceable in a guideway 172 ontht strut and by a single-member swivel arm 125 which is attached at oneend to thestrut 112 and at the other end to the telescopic guide memberby a dog attachment 155 Which either slides on the inner tube 120 (inthe case of the shortened sleeve tube shown in FIGURE 16) or on sleevetube 130 (in the case of a sleeve tube which is recessed on only oneside as shown in FIGURE 20).

The tube arrangement of FIGURES 17 and 19 is best explained on the basisof FIGS. 21C and 21D. In this embodiment the sleeve tube 130 slides oninner tube 120 formed by the thrust cylinder 170. To permit the innertube 120 or cylinder 170 to be connected at both ends with itsappropriate strut 111 without having to slot the sleeve tube 130, theinner tube 120 (of cylinder 170) is connected firmly with a slotted tube140 which, in turn, partially encircles the sleeve tube 130 clawfashion.This duplication of the guidance for the sleeve 130 is of particularadvantage where the inner tube is in the form of cylinder 170, thepiston rod of which is to be protected from damage. The arrangement canalso be simplified by dispensing with the tube 120 altogether in whichcase the tube 130 is the inner tube upon which the slotted tube 140slides.

Axles 192 are located on extensions of tube 140 and the tube 130,opposite and in alignment with axles 191 which are located on the struts111 and 112. Arms 193, 194, 195, 196 are pivoted on the axles 191 andarms 193', 194, 195', 196' of the two-member swivel arm are pivoted onaxles 192. Between the arms 193, 193' and the arms 194, 194', a pivotjoint 197 is interposed. In normal position the axles 191 and 192 andthus arms 193 and 193, and arms 194, 194 etc., are at the same level butif the tubes 140, and 130, fall in relation to the struts 111 and 112respectively, or if they rise, the axles 191 and 192 separateaccordingly and the two-member swivel arms 193 and 196 openscissors-fashion at the joint 197, this opening movement beingcounteracted by drawsprings 198.

In FIGURES 18 and 22 the sleeve tube 160 connected to the strut 111 islongitudinally slidable on an inner tube 150' (the thrust cylinder 180),while the sleeve tube 160 connected to the strut 112 is longitudinallyslidable on the inner tube 150 (the thrust cylinder 180), so that thesleeve tube 160" connected to the strut 111 is connected rigidly withthe inner tube 150 (thrust cylinder 180) on the assembly connected tothe strut 112. In the 7 same manner the reverse applies, the sleeve tube160 being joined rigidly with inner tube (thrust cylinder 180'). Theconnecting members between the sleeve tube and the strut 111, betweensleeve tube 160 and strut 112, are of identical construction to thoseshown in FIGURES 2 and 6, but can equally well be constructed in theform illustrated in FIGURES 16 and 20.

It is not necessary to deal in detail with the process whereby thesupport assemblies are moved with the aid of the thrust cylinders andrespectively. FIGURES 16 to 19 illustrate the manner in which this-iscarried out using a rope, the rope being led respectively around thecoalface side of prop 104 and around the backfill side of prop 106. Ropetraction is achieved with the aid of a winch set up at the lower end ofthe coalface, with respect to the group of frames to which the rope isat tached. After releasing the frame bearing strut 112 of FIGURE 18, theframe is pushed forward until prop 105 reaches the row containing prop103 and prop 106 reaches the row containing prop 104. The frame is thensettled anew and the frame bearing strut 112 of FIGURE 17 is releasedand advanced appropriately.

In the next seam a rope is used in the appropriate manner, being laidaround the coalface side of prop 105 in each case and around thebackfill side of prop 104, Both ropes can be carried permanently on thesupport frames, each being operated by its own winch set up at the lowerend of the appropriate frame group and wound back on to a winch mountedon the upper end of the frame group after the group has been advanced.In this case it is necessary to the upper winch to be blocked while therope assigned to it is wound on to the lower winch, while on the otherhand the upper winch to which the other rope is assigned must permit therope which it carries to be unwound. The frames in the first pair in thegroup are not advanced by the rope but, for example, by the thrustcylinders.

What I claim is:

1. A roof support assembly comprising a pair of relatively moveableframes each of which comprises a floor strut and a roof strut eachjoined by two vertical props, guide members interposed between therespective floor struts and roof struts of each said frame, extensiblemeans forming a part of each guide member, a pivotal connection betweeneach extensible means and the respective floor and roof struts forenabling relative pivotal movement of the respective frame and guidemember, and operative connections between each guide member and therespective floor and roof struts of each frame, each operativeconnection including a pivotal joint to enable rocking movement of theparticular strut relative to the respective guide member, a joint toenable longitudinal shifting of each frame relative to the respectiveguide member, and a joint to enable vertical movement of each framerelative to the respective guide member.

2. A roof support assembly comprising a pair of relatively moveableframes, each frame having a floor strut and a roof strut, two verticalprops joining the floor and roof struts of each frame, a guide memberinterposed between said floor struts, saide guide member comprising tworelatively shiftable parts, means for rockably connecting one shiftablepart to one floor strut, means for rockably connecting the othershiftable part to the other floor strut, means for slideably connectingsaid guide member to one floor strut enabling relative vertical movementthereof, and means for slideably connecting said guide member to theother floor strut enabling relative vertical movement thereof.

3. A roof support assembly as claimed in claim 2, in which said rockableconnection at each outer end of said shiftable parts comprises atrunnion attached to the respective frame at a point spaced in thevertical direction from the strut with which such shiftable part isassociated.

4. A roof support assembly as claimed in claim 2, in

which at least the guide member interposed between the floor struts istelescopic and constructed as a double thrust cylinder having pistonsacting in opposite directions.

5. A roof support assembly as claimed in claim 2, in which each frame isattached to its associated slidable part of the guide member by twodouble swivel arms each comprising two links pivotted together at oneend and attached at their other ends by trunnions respectively to theguide member and the frame and being adapted to pivot in scissorsfashion about the axis of the pivotted ends.

6. A roof support assembly as claimed in claim 5. in which thedouble-swived arms connecting each frame to the guide member are locatedbetween and in alignment with the guide member and the frame with theaxes of the pivotted ends of the swivel arms on each side of the guidemember adjacent one another and interconnected by a spring.

7. A roof support assembly as claimed in claim 6, in which the swivelarms are permanently biassed into parallel relation with the struts ofthe associated frames by springs anchored to a support on the pivotalaxes of the swivel arms.

8. A roof support assembly as claimed in claim 6, in which the swivelarms are blessed in a direction transverse to the length of the strutsof the frames.

9. A roof support assembly comprising a pair of relatively moveableframes, each of which comprises a floor strut and a roof strut, twovertical props joining each floor strut and a roof strut, a guide memberinterposed between the floor struts of the two frames, the guide memberin the form of two parts slideable along each other, each of whichcomprises a tube and a spaced parallel extending sleeve, means forinterengaging the tube and sleeve on one sideable part with the sleeveand tube on the other sideable part, and means for pivoting eachslideable part to a frame, said pivoting means including two connectingmembers enabling relative vertical movement between the slideable partand the frame.

10. A roof support assembly as claimed in claim 9, in which the sleeveis slotted and the connecting members attached to the tube projectthrough the slot.

11. A roof support assembly as claimed in claim 10, in which the sleeveis an enclosed tube having a recess at one end accommodating theconnecting member which attaches the inner tube directly andnon-displaceably to the associated frame, the other connecting member onthe associated frame being mounted on a dog attachment which islongitudinally and vertically slidable on the sleeve or inner tube.

12. A roof support assembly as claimed in claim 11, in which the sleevewhich is in the form of an enclosed tube is encased by anon-displaceable slotted tube attached to and coxial with the innertube, the inner tube being constructed and acting as a thrust cylinderand the connecting members between the sleeve and its associated frameprojecting through the slot in the non-displaceable tube.

References Cited UNITED STATES PATENTS 1,594,921 8/ 1926 Barnett 61453,169,377 2/1965 Hoifmann 6145 3,197,965 8/1965 Lee et a1. 61-453,197,966 8/1965 Arnott 6145 3,241,323 3/1966 Grisebach 61-45 FOREIGNPATENTS 968,117 8/ 1964 Great Britain. 1,091,525 10/1954 France.

970,540 10/ 195 8 Germany. 1,156,037 10/ 1963 Germany. 1,159,884 12/1963 Germany. 1,166,127 3/1964 Germany.

DENNIS L. TAYLOR, Primary Examiner.

DAVID J. WILLIAMOWSKY, Assistant Examiner.

